Process for producing or stripping dyeings



2,903,325 Patented Sept. 8, 1959 PROCESS FOR PRODUCING OR STRIPPINGDYEINGS Wilhelm Geigy, Binningeu, Switzerland, assignor to Ciba Limited,Basel, Switzerland, :1 Swiss firm No Drawing. Application May 13, 1957Serial No. 658,527

Claims priority, application Switzerland January 29, 1954 8 Claims. (Cl.8-43) This application is a continuation-in-part of my copendingapplication Serial No. 484,057, filed January 25, 1955 (and abandonedsince the filing of the present application).

This invention is based on the observation that polyvinyl-pyrrolidone,if desired, in conjunction with another ion-free agent, is a goodlevelling agent or stripping agent in the production or stripping ofdyeings on nitrogenous basic fibrous materials of complex metalcompounds, especially chromium or cobalt compounds, of monoazodyestuffsfree from sulfonic acid groups and containing less than one atomicproportion of metal boundin complex union per molecular proportion ofmonoazo-dyestufif.

For the purposes of the present invention ordinary commercialpolyvinyl-pyrrolidone may be used. There are suitable e.g.polyvinyl-pyrrolidones having a molecular weight ranging from 5000 to50,000 (average 25,000), those having a molecular weight ranging from20,000 to 80,000 (average 50,000) or those having an average molecularweight of 700,000. As ion-free agents which may, if desired, be used inconjunction with the polyvinyL pyrrolidone there come into considerationmore especially ethylene oxide condensation products of fatty alcohols,of fatty amines or of alkyl-phenols. There may be mentioned, forexample, the condensation product of 1 molecular proportion ofpara-tertiary-octyl-phenol with about 8 molecular proportions ofethylene oxide or the condensation product of 1 molecular proportion ofoctadecyl alcohol with about 25 molecular proportions of ethylene oxide,and also the condensation product of 1 molecular proportion ofoleylamine with about 12 molecular proportions of ethylene oxide. Therelative proportions of the polyvinyl-pyrrolidone and the other ionfreeagent may vary within wide limits, but there are advantageously usedmixtures of which at least one half consists of polyvinyl-pyrrolidone.

The dyeing with a complex metal compound of the kind described above, ofwhich a large number is known in the literature, is carried out in theusual manner. The levelling agent may simply be added to the dyebath.The proportion in which it is added usually amounts to a few parts permil on the weight of the fibrous material.

The stripping of a dyeing by the process of the invention isadvantageously carried out at a raised temperature, for example, at theboiling temperature. For this purpose it usually suffices to use a fewparts percent of the stripping agent calculated on the weight ofthefibrous material. If desired, a reducing compound, such as ahydrosulfite, may also be added.

As nitrogenous basic fibrous materials, on which a dyeing may beproduced or from which a dyeing may be stripped, there come intoconsideration more especially wool, and also silk or synthetic fibershaving similar properties obtained from casein or polyamide orpolyurethane fibers. There may also be used mixtures of basic fiberswith other fibers, for example, nitrogenous non-basic fibers, such aspolyacrylonitrile fibers, and also fibers of polyvinyl chloride orpolyester fibers. The fibrous material may be treated in loose conditionor in the form of a yarn, hank or fabric, or in the form of foil. Thepresent process is especially suitable for the treatment of wool.

The following examples illustrate the invention, the parts being byweight unless otherwise stated and the relationship of parts by weightto parts by volume being the same as that of the kilogram to the liter.

Example 1 W001 is dyed at the boiling temperature in a dyebath, whichhas been adjusted with sodium phosphate to a pH value of 6.5 andcontains 0.25% of the bordeaux dyeing cobalt complex of the dyestufi ofthe formula OH OH 01 SiOaNHg Cl and 0.25% of a mixture of equal parts ofpolyvinylpyrrolidone and the condensation product of one molecularproportion of commercial octadecyl alcohol with about 25 molecularproportions of ethylene oxide. (The percentages are calculated on theweight of the fibrous material). The dyeing is then finished in theusual manner. There is obtained a substantially more level dyeing thanis obtained without the addition of the levelling agent.

In the same manner the yellowish red dyeing chromium 1:2 complex of thedyestuff of the formuia can be used to produce more level dyeings.

Similar results are obtained by using polyvinyl-pyrrolidone alone,instead of the aforesaid mixture.

Example 2 In order to strip a dyeing the procedure may be as follows:Wool, which has been dyed with 1% of the reddish blue dyeing chromiumcomplex of the dyestutt of the formula is treated for one hour at theboiling temperature and at a liquor ratio of 1:40 in a bath whichcontains 4% of polyvinyl-pyrrolidone calculated on the weight of thefibrous material. The material is then rinsed and dried. The dyestufi isstripped to a considerable extent in this manner.

A smaller quantity of polyvinyl-pyrrolidone may be used, for example, 1or 2% and in this manner the dyeing is rendered considerably lighter.

Instead of using polyvinyl-pyrrolidone a1one,there may be used themixture described in Example 1 or a mixture 3 of 'polyvinyl pyrrolidoneand a condensation product of 1 -molecular-proportion of -oleylamine and-10-14-molecular proportions of ethylene oxide.

Example 3 k A wool fabric is dyed at the boiling temperature in-adyebath which has been adjusted with ammoniumacetate to a pH value of6.3 and contains 0.25% of the reddyeing cobalt :1 :2 complex of thedyestulf of the formula on on formula OH OH SOZNHCHS The red dyeingcobalt 1:2 complex of the dyestufi of the formula OH OH OgNHCH OHaOH Thesteel blue dyeing chromium 1:2 complex of the dye- "stufi of the formulaOHNS I S OiNHl Similar results are obtained by using apolyvinyl-pyrrolidone having an average molecular weight of 700,000instead of a polyvinyl-pyrrolidone having an average molecular weight of40,000.

Example 4 A'wool fabric is dyed at the boilingtemperature in a dyebathwhich has been adjusted with ammonium acetate to a pH value of 6.3 1 andcontains -'0Z25% of the" brown .4 dyeing chromium 1:2 complex of thedyestufi of the formula and 0.2 ofapolyvinyl pyrrolidonehavingan averagemolecular weight 40,000. '(The percentages are calculated on the weightof the fibrousmaterial.) The dyeing is then finished in the usualmanner. There is obtained a substantially morelevel dyein g 'than isob'tained without the addition of the levellingagent.

In the same manner, the brownish'red dyeing cobalt 1:2 complex of theformula .can'beused to=produce more level dyeings.

Similar-results areobtained by using a polyvinyl-pyrrolidone having anaverage molecular weight of 700,000

instead of a polyvinyl-pyrrolidone having an average molecular weight of40,000.

Example 5 A Wool fabric is dyed atthe boiling temperature in a dyebathwhich has been adjusted with ammonium acetate to a pH valueof 6.3 andcontains 0.25% of the green dyeingcobalt 1:2-complex'of the dyestufi ofthe formula and 0.2% of a'polyvinyl-pyrrolidone having an averagemolecular 'weight-of"700, 000. (The percentages are-calculated-ontheweight of the fibrous materiaL) The dyeing is then finished inthe'usual manner. There is obtained a subs'tantiallv'more level dyeingthan is obtained "without the addition of the levelling agent.

'In the same'manner the following metal complexes of monoazo-dyes'tufiscan be'used to produce more level dyeings: v

The lilac dyeing chromium 1:2 complex of the dyestufl? of the formulaThe-greendyeing-chromium 1:2 complex or the greyis'hviolet dyeing cobalt1:2 complex of the dyestufi of the "formula OH OH The greyish greendyeing chromium 1:2 complex of the dyestufi of the formula OH OH OzN ENAnd the steel-blue dyeing chromium 1:2 complex of the dyestufl? of theformula I THCOOH 1 Similar results are obtained by using apolyvinyl-pyrrolidone having an average molecular weight of 40,000instead of a polyvinyl-pyrrolidone having an average molecular weight of700,000.

What is claimed is:

1. In the process of shifting the distribution equilibrium, between anaqueous dye bath and wool, of a complex metal compound of a monoazodyestuff which is free from sultonic acid groups O -catlon and containsless than one atomic proportion of a metal selected from the groupconsisting of cobalt and chromium bound in complex union per molecularproportion of dyestuir", the improvement of simultaneously incorporatinginto said aqueous bath polyvinyl-pyrrolidone, in addition to said wooland said complex metal compound.

2. In the process of shifting the distribution equilibrium, between anaqueous dye bath and Wool, of a complex metal compound of anortho,ortho'-dihydroxy-monoazo dyestutf which is free from sulfonic acidgroups O-cation and contains less than one atomic proportion of a metalselected from the group consisting of cobalt and chromium bound incomplex union per molecular proportion of dyestufi and which furthercontains at least one sulfamide group in an aromatic nucleus, theimprovement of simultaneously incorporating into said aqueous bathpolyvinyl-pyrrolidone, in addition to said wool and said com.- plexmetal compound.

4. In the process of shifting the distribution equilibrium, between anaqueous dye bath and wool, of a com- 6 plex metal compound of anortho,ortho'-dihydroxy monoazo dyestufi which is free from sulfonic acidgroups O-cation and contains less than one atomic proportion of a metalselected from the group consisting of cobalt and chromium bound incomplex union per molecular proportion of dyestuff and which furthercontains at least one sulfamide group in an aromatic nucleus, theimprovement of simultaneously incorporating into said aqueous bath polyvinyl-pyrrolidone and a condensation product of a fatty alcohol withethylene oxide, in addition to said wool and said complex metalcompound.

5. In the process of shifting the distribution equilibrium, between anaqueous dye bath and Wool, of a complex metal compound of anortho,ortho-dihydroxy monoazo dyestuif which is free from sulfonic acidgroups O-cation and contains less than one atomic proportion of a metalselected from the group consisting of cobalt and chromium bound incomplex union per molecular proportion of dycstuif and which furthercontains at least one sulfa-mide group in an aromatic nucleus, theimprovement of simultaneously incorporating into said aqueous bathpolyvinylpyrrolidone and the condensation product of 1 molecularproportion of octadecyl alcohol with about 25 molecular proportions ofethylene oxide, in addition to said wool and said complex metalcompound.

6. In the process of shifting the distribution equilibrium, between anaqueous dye bath and wool, of a complex chromium compound of anortho,ortho'-dihydroxy monoazo dyestutf which is free from sulfonic acidgroups O-cation and contains less than one atomic proportion of chromiumbound in complex union per molecular proportion of dyestuff and whichfurther contains at least one sulfonamide group in an aromatic nucleus,the improvement of simultaneously incorporating into said aqueous bathpolyvinyl-pyrrolidone, in addition to said wool and said complexchromium compound.

7. In the process of shifting the distribution equilibrium, between anaqueous dye bath and wool, of a complex cobalt compound of anortho,ortho-dihydroxy monoazo dyestuff which is free from sulfonic acidgroups and contains less than one atomic proportion of cobalt bound incomplex union per molecular proportion of dyestuif and which furthercontains at least one sulfonamide group in an aromatic nucleus, theimprovement of simultaneously incorporating into said aqueous bathpolyvinylpyrrolidone, in addition to said wool and said complex cobaltcompound.

8. In the process of shifting the distribution equilib rium, between anaqueous dye bath and Wool, of a complex metal compound of anortho,ortho'-dihydroxy monoazo dyestufi which is free from sulfonic acidgroups O-cation and contains less than one atomic proportion of a metalselected 'from'the :group consisting'of cobalhand chro- 'ular:proportionsof ethylene oxide in addition-to :said

mium bound in icomplex union-per mole'culanproportion wool and saidcomplex metal compound. of dyestufi and which further contains at leastone sulfamide group in an aromatic'nucleus, the improvement ofReferences Cited in the me of this PAtent simultaneously incorporatinginto said aqueous bath a Melliand, XXXII, "for January 1951, pp. 53-56.polyvinyl-pyrrolidone andzthe condensation product of 1 AmericanDyestuff Reporter for Feb. 1, 1954, pp.

molecular proportion of .oleylamine with 1010 14 molec- 7 75.

1. IN A PROCESS OF SHIFTING THE DISTRIBUTION EQUILIBRIUM, BETWEEN ANAQUEOUS DYE BATH AND WOOL, OF A COMPLEX METAL COMPOUND OF A MONOAZODYESTUFF WHICH IS FREE FROM SULFONIC ACID GROUPS